ACOS

ACOS returns the arc cosine of n. The argument n must be in the range of -1 to 1, and the function returns a value in the range of 0 to pi, expressed in radians.

This function takes as an argument any numeric datatype or any nonnumeric datatype that can be implicitly converted to a numeric datatype. If the argument is BINARY_FLOAT, then the function returns BINARY_DOUBLE. Otherwise the function returns the same numeric datatype as the argument.